Attachment-plug.



C. J. KLEIN.

7 ATTACHMENT PLUG. APPLICATION FILED OCT. 28; l9I3- 1,171,852. 1 Patented Feb. 15,1916.

hrs. eras lea.-a ante orsion.

CHARLES J. KLEIN, OF MILWAUKEE, WISCONSIN.

ATTACHMENT-PLUG.

airless.

Specification of Letters Patent.

Application filed October 28, 1913. Serial No. 797,874.

To all whom it may concern:

Be it known that I, CHARLES J. KLEIN, a citizen of the United States, residing at Milwaukeain the county of Milwaukee and State of 'isconsin, have invented new and useful Improvements in Attaclnnent-Plugs,

of which the following'is a full. clear, concise, and exact description. reference being had to the accompanying drawing, forming a part of this specification.

This invention relates to attachment plugs for electrical devices.

One of the objects" of the invention is to fully and clearly I have illustrated one embodiment oft-he same in the accompanying drawing.

Figure 1 is a sectional view on the line 11 of Fig. 2. Fig. 2 is a section of the plug atright angles to Fig. 1. Fig. 3 is a sect onal view of the plug on the line 83 of F ig. 2. Fig. i is a bottom View of the plug; and, Fig. 5 is an enlarged detail View of the resilient locking and contact members.

The plug shown comprises twobase members 1 and 2 of semi-cylindrical form. The plane faces of these parts fit together as shown and are held in position by a threaded conducting shell 3. The plug has a conductor opening 4: in its upper end leading.

to an enlarged chamber 5. Terminals 6 and 7 are seated in the base by suitable means, such as screws 8 and have binding posts 9 at their upper ends within the chamber 5. These parts are substantially similar to those described and claimed in my copending application, filed Jan. 13, 1913, Serial No. 741,773, but in this case the shell 3 is locked against accidental removal by the novel means described hereinafter. The

.outer end of the contact shell 3 is provided.

- screw 8.

with ,an inturned portion 10 bent at right angles to the sides of the shell. A series of segmental openings 11 are cut through the inturned portion at regular intervals thereabout. The terminal 7 on the base member -2 emerges from the lower end thereof through a central circular insulating wall 12. The end of this terminal is provided with a central contact disk13. The other terminal 6 is preferably shorter and extends only a slight distance beyond its securing cured to the terminal 6 and the base 1 by a, screw 8.- These members extend through the lower face of the plug at one side of the wall 12 and are bent at right angles in the form of arcs lying substantially parallel to' the face of the plug and partially encircling the insulating wall 12. The locking member 15 is provided with a segmental catch 16 at its extremity formed by upturning a limited portion of its edge to form an arched and hooked projection. The outer face of Patented Feb. 15, 1916 A resilient contact member 11 and p a resilient locking member 15 are also sethe catch 16 is beveled and merges in an unbroken line' into the edge of its fiat surface. This member is also provided with'an upturned tongue 17 on its inner circumference adapted to protrude between the wall 12 on the plug and the flanged margin of the conducting shell. The tongue is thus accessible when the parts are assembled and may be pressed to compress the member 15 and release the catch 16 from its coiiperating shoulder on the conducting shell, as will appear hereinafter. The contact member 14 underlies the lockingmember 15 and isbent outwardly at an angle beyond the end of the latter to rise beyond the plane thereofand then again bent parallel with the lower face of the plug to form a resilient fiat contact 1S. This contact is adapted to press upon the flanged margin of the conducting shell to establish electrical contact between the same and the terminal 6.

The operation of the locking elements described is as follows: As the conducting shell is screwed on the reduced end of the plug the inturned portion 10 of the former approaches the arc-shaped res lient locking member 15 and the resilient contact 18.

After predeterminedpartial attachment the inturned portion 10 engages the extremities of both resilient members. The projecting catch on the member 15 then enters one of the openings 11 in the inturned portion of the shell, whereupon the shoulder of the .catch 16 engages the straight out edge of the opening 11 in the shell and prevents reverse rotation of the latter. Further rotation in the same direction, however, is permitted until the upper edge of the shell abuts the annular shoulder 19 of the base. During such additional rotation the beveled face of the projecting catch 16 is resiliently urged out of one segmental opening 11 and successively snaps into the adjacent opening. The resilient contact 18 at the same time presses upon the inturned portion 10 of the shell to maintain constant electrical contact between thesame and. the terminal 6. Removal of the shell is readily obtained by pressing the tongue 17 between the insulating wall 12 of the base and the inturned marginal portion 10 of the shell, and thus depressing the resilient locking member 15 until the shoulder thereon is disengaged from its corre sponding opening in the inturned portion, when the shell may be unscrewed. It is to be noted that the catch 16 will engage the straight edge of the opening 11 of the conducting shell and very eiiectively prevent reverse rotation of the latter, since as soon as the catch snaps into an opening all tendency to unscrew the shell will result in. the hooked face of the catch gripping the edge of the opening more firmly. In other words, forward rotation of the shell operates to separate the catch and marginal. flange while reverse rotation operates to press them. more firmly together. The outer portion of the conducting shell is preferably cylindrical,

as shown, and only the upper half of the shell is threaded. By this means, attachment of the shell to the plug is readily accomplished by a minimum number of turns. Furthermore, the insertion of the assem bled plug into a receiving socket is also facilitated.

While I have illustrated. one preferred form of my improved device, it is to be understood that the specified form herein shown is susceptible of modification without departure from the spirit of the invention, or the scope of the appended. claims.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a longitudinally divided base, a threaded conductingshell rotatably mounted thereon to hold the parts of said base together,'said shell having a plurality of circumferential shoulders, and a resilient member carried by said base having a projection thereon adapted to engage a shoulder of said shell in any one of a plurality of rotary positions of the latter to automatically lock the same against reverse rotation.

2. -An attachment plug comprising a base and a conducting shell rotatably threaded thereon, said shell having an inturned marginal portion. provided with a plurality of circumferential. shoulders thereon, a member carried by said base having a yieldable portion adapted to engage any of said shoulders to lock said shell against reverse rotation, and a resilient terminal member carried by said base for establishing electrical connec tion with said shell independently of said first mentioned member.

3. An attachment plug comprising a base and a conducting shell mounted thereon having an inturned marginal portion. provided with a plurality of shoulders, a resilient contact member secured to said base and electrically engaging said marginal portion of said shell, and a resilient member superposed on said contact member having a shoulder adapted to successively engage said first mentioned shoulders to lock said shell against reverse rotation.

4. In electrical contact devices, in combination, a rotatable conducting member pro vided. with a series of shoulders concentrically located with respect to its axis, a resilient contact member adapted to press upon said conducting member and a resilient locking member superposed on said contact member having a shoulder adapted to successively engage said first mentioned shoulders as said conducting member is rotated to lock the latter against reverse rotation. v

5. In combination, a base, a conducting shell threaded thereon, a terminal member seemed to said base and establishing electrical connection with said shell and a resilient member adjacent on said terminal member and having a part to engage and lock said shell against rotation.

6. An attachment plug comprising in. combination, a two-part longitudinally divided base having a conductor opening and a threaded portion, a pair of conducting members carried by said base having inclosed binding posts adjacent said conductor opening and exposed terminals at the threaded end of said base, said binding posts being accessible for connection with line wires when the parts of said base are separated,

and a conducting shell threaded interiorly for screwing upon the threaded portion of said base and holding the parts thereof together and threaded exteriorly for screwing into a complementary receptacle, said shell having an inturned portion at its free end adapted to electrically connect with one of rotation in any one of a plurality of rotary positions with respect to said base.

In testimony whereof, I have hereunto subscribed my name in the presence of two witnesses.

CHARLES J. EIN} Witnesses:

S. F. WATSON, F. H. HUBBARD. 

